Targeted mutagenesis of the human chemokine (C-C motif) receptor 5 gene using zinc finger nucleases and TAL effector nucleases

Abstract

Genome engineering that allows targeted mutagenesis and gene correction in higher eukaryotic cells and organisms is broadly useful in research, biotechnology, and molecular medicine. Zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs) are artificial DNA-cleaving enzymes composed of the FokI nuclease domain and custom-designed arrays. ZFNs and TALENs are powerful and versatile tools of genome engineering that induce site-specific DNA double strand breaks (DSBs) in the genome, whose repair via homologous recombination or non-homologous end-joining (NHEJ) gives rise to gene correction and disruption. Here I describe an efficient and easy-to-practice modular-assembly method using available zinc fingers to make ZFNs. Also, I report the DNA-binding modules of TAL effectors (TALEs) derived from plant pathogens can substitute zinc fingers to make the TALENs. Using this method, I synthesized and tested hundreds of ZFNs and TALENs to target genes of different sites in the human CCR5 gene that is a co-receptor required for HIV infection and found that many of these nucleases induced site-specific mutations in the CCR5 sequence. Because human cells that harbor CCR5 null mutations are functional and normal, these ZFNs and TALENs might be used for knocking out CCR5 to produce T cells that are resistant to HIV infection in AIDS patients.